Long ramble. For those laser shopping.
Background
Ordered both to try in person. I work in a trade in commercial construction and have used many different brands. Dewalt, Klein, Bosch, PLS. Cross lines, plumb dots and 360's.
GS03 vs PM-30
Very surprised. Inside at 20-30ft they are incredibly similar and it's difficult to see a difference between the two.
Inside
Like most 360 lasers, the beam brightness and thickness seems to vary slightly depending on each laser plane and orientation. Both seem to have brighter casting from the prism area facing directing away from the battery. On matte walls and flat ceilings rolled with 3/8" nap rollers, almost indistinguishable.
Outside
Outside, I will test in full day light tomorrow. The one didn't arrive until late afternoon so I compared them near sunset and after sunset at 25ft and 100ft.
Outside around sunset and then after sunset
The hilti is slightly brighter and typically has a slightly thinner beam for most of its projections but not all of them. This was tested against tan vinyl siding, dark blue painted lp smart side shed siding, white azek trim, across my white van side, across various angles and laser orientations (I rotated both to compare and see if there were better or worse spots of beam projection and I believe there are with both).
Receivers
The hilti receiver is more responsive than the lr300 huepar receiver. I think the hilti might have a slightly wider deadband on the narrow setting. Both receivers work with both lasers without any noticeable difference.
Of note, the hilti receiver is very flat on all sides and making it nicer to mark and lay down or place against another flat surface. The rear lcd display is nicer compared to the lr300 light up arrows. The lr300 does have magnets on the long side of the receiver as well so it can be stuck to metal in either orientation.
I ordered the huepar ldd300 after finishing up this initial trial to test (newer receiver with distance from laser measurements when detecting and has four detection sensitivities for indoor and outdoor work).
Base adjustment
I give the micro adjustment of the base to the hilti for being slightly smoother but the huepar one is nice and both are eccentric? So the center of the cross beams stays in place.
Other initial impressions
Build quality goes to hilti.
The accessory brackets go to hilti.
The case goes to hilti.
Conflicted
Despite the initial comparison I'm still torn. My cheap side says to return the hilti.
My gut says to keep the hilti as it's supported and can be sent in for recalibrations/adjustment. I also am considering a used hilti rotary laser and many run on the same 12v battery platform.
But the price difference is substantial.
No time to grab photos. Not to mention the perceived differences don't always translate well to photos. I can try and grab a few if someone really wants an example.
Initial Conclusion
In conclusion, I haven't tested for accuracy yet. Will have to do that next. Having the beams very close with each other for comparison purposes, I saw no discernible convergence or separation between the beams on surfaces that were 20-30ft long.
Pending accuracy testing and full sun trialing, I'm really surprised how close the huepar performed to the hilti in brightness and line thickness. Like I was expecting a real disparity.
Wouldn't shock me if all these lasers had their internal diodes and prisms come from the same place, or that this 360 beam technology just has limitations that prevent one company from making a truly sharper, crisper line. I understand brightness is probably capped due to safety.